Cabinet construction



Oct. 1, 1957 Filed March 7; 1955 E. H. MAGESTER CABINET CONSTRUCTION 2 Sheets-Sheet 1 INVENTOR.

EARL H. MAGESTER HIS ATTORNEY Oct. 1, 1957 E. H. MAGESTER CABINET CONSTRUCTION 2 Sheets-Sheet Filed March '7, 1955 F'IG.7

' INVENTOR.

EARL H. MAGESTER HIS ATTORNEY United States Patent CABINET CONSTRUCTION Earl H. Magester, Louisville, Ky., assignor to General Electric Company, a corporation of New York Application March 7, 1955, Serial No. 492,708

Claims. 01. 312-257 My invention relates to sheet metal cabinets, as for example refrigerator cabinets, and more particularly to the construction of the outer shell of such cabinets.

It is an object of my invention to provide an improved shell member for sheet metal cabinets.

It is another object of my invention to provide an improved sheet metal shell member of the type having integral reinforcing sections extending along the longitudinal edges thereof.

It is a further object of my invention to provide a new and improved corner construction for sheet metal shell members having channel sections extending along their longitudinal edges, which construction permits the shell members to be formed with generally square corners.

Another object of my invention is to provide a new and improved method for forming a sheet metal shell member having integral channel sections extending along the edges thereof.

A further object of my invention is to provide a new and improved method for forming strong rigid corners in reinforcing sections extending along the edges of a sheet metal shell member.

My invention also has as its object the provision of a new and improved sheet metal blank adapted to be formed into a shell member having integral channel sections along the longitudinal edges thereof.

. In carrying out my invention, 1 provide an improved outer shell member for a sheet metal cabinet. This shell member includes at least two walls and it is formed from a single sheet of material, the sheet being folded or bent to form the walls of the shell. To strengthen the shell its walls have a stiffening and reinforcing section extending along at least a portion of one edge thereof. This section comprises an integral part of the walls, being formed from the same sheet of material, and it includes a double thickness flange. At the corner between the walls of the shell the reinforcing section is provided with a new and improved construction whereby a particularly strong and rigid corner is produced. In this corner construction a generally mitered joint is formed in one thickness of the flange, and the other thickness is so arranged that a portion thereof overlaps and reinforces the mitered joint without any overlapping occurring in the other thickness itself. In this manner a strong rigid corner structure is formed in the reinforcing section, and thereby a rigid corner construction is effected in the shell member as a whole.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a perspective view of a preferred embodiment of my new and improved sheet metal shell member, the view being partially cut away to show the channel sections included therein;

Fig. 2 is a fragmentary frontal view of the front righthand corner of the shell member of Fig. 1, the view showing details of the new and improved corner construction used in the channel sections of the shell member;

Fig. 3 is a fragmentary sectional view taken on the line 33 of Fig. 1 and showing the front right-hand corner as viewed from the rear of the outer flange of the channel section;

Fig. 4 is a plan view of the sheet metal blank from which the shell member of Fig. 1 is formed;

Fig. 5 is a fragmentary view of the front channel section of the shell before the blank is bent into the form of the shell, the view looking upwardly toward the main surface of the blank;

Fig. 6 is a fragmentary sectional view taken on the line 6-6 of Fig. 5 showing the outer flange of the channel section as viewed from the front before the blank is bent into-the form of the shell; and

Fig. 7 is a fragmentary sectional view taken on the line 77 of Fig. 5 and showing the outer flange of the channel section as viewed from the rear before the blank is bent into the form of the shell. I v

Referring now to Fig. 1, I have shown therein a sheet metal shell member particularly adapted for use in a refrigerator cabinet. This shell member, generally designated at 1, includes a top wall 2 and side walls 3 and 4 which are all formed from a single sheet of material.

On both their front and rear edgesthese walls include a channel section formed integrally therewith. Specifically, the frontedge of the shell has an integral channel section Sand the rear edge has an integral channel section 6.

These channel sections stiffen the shell and help prevent it from deforming both during its incorporation into a cabinet and during later use.

Both the channel sections include a double thickness outer flange, a single thickness inner flange and an intermediate portion joining the two flanges. Thus the front channel 5 includes an outer double thickness flange 7, an inner single thickness flange 8, and connecting portion 9; and the rear channel section 6 includes an outer double thickness flange 10, an inner single thickness flange 11 and an intermediate portion 12. It will be noted that the intermediate portions 9 and 12 lie parallel to and are in contact with the main section of the walls of the refrigerator. Such an arrange ment adds materially to the stiffening effect provided by the channel section.

By my invention strong rigid corners are formed in the channel sections and thereby in the shell member itself. The right-hand and left-hand corners in the channel sections incorporate the same basic structure. Further the corner structures are basically the same in both the front channel section 5 and the rear channel section 6, the

structures in the rear channel differing from those in the front channel only in size. The construction of the front right-hand corner may thus be taken as exemplary of the construction of the other corners and consequently only that one corner will be described herein in detail. It is believed that a description of it and its method of formation will give a full understanding of my invention.

In my new and improved corner construction the front thickness of the outer flange is so arranged that a generally mitered joint is formed therein at the cornersbetween the walls. For example, a generally mitered joint 13 is formed in the outer thickness 14 of the flange 7 at the corner 15 between the walls 2 and 4 of the shell. The rear thickness 16 of the outer flange however does not include such a mitered joint. Rather, by my invention, it is so arranged that it overlaps and reinforces the mitered. joint in the front thickness.

of the flange 7 is arranged at the corner '15 to overlap Patented oct. 1, 1957 an intermediate or Thus the rear thicknessld and reinforce the joint 13 in the front thickness without there being any overlapping in the rear thickness 16 itself; The rear thickness 16 by so overlapping or backing up the joint 13. inthe front thickness 14 allows a stronger, more rigid'corner to he formed than has heretofore been available. The corner construction is completed by a weld which both attaches together the edges forming the mitered joint 13 and. thefront and rear thicknesses154' and 1:6. gether the edges of the front thickness. at the joint and also welds the rear thickness to the front thickness behind the joint. The continuous thickness. or layer behind the joint thereby is permanently. attached thereto. so that it will aid greatly in taking .upany strain applied'to the joint. As aresult, 'a. particularly strong corner is provided in. the channel section and thereby. the corner between the walls is made more rigid as'a whole. It will be noted thatthis construction also has the particular advantage of permitting a generally square or right-angle corner to be formed in the shell. g

The'rear' single thickness iiangev 8 may he merely notched or recessed at the corners so that the portion extending along one of the walls overlaps the portion. extending along the other wall: For example, the portionlTextending along the wall 41nay overlap the portion 18 extending along the wall 2. This overlapping is-shown by-the'dotted linesin Fig. 2.

My improved cabinet shell member and its novel corner construction may perhaps be best understood by a description of the method in which it is formed. I will therefore now describe that method, having particular reference to Figs; 2-8. Referring first to' Fig. 4, I have shown therein a rectangular sheet metal blank '19 from which the shell 1 may be formed. This blank .19 has two spaced-apart apertures cut therein adjacent each of its longitudinal edges. are cut out adjacent the front edge of the blank and apertures 22 and 23 are cutout adjacent the rear edge of the blank. These apertures may be formed by any suitable method as by a punch press operation and, as explained hereinafter, they provide a means whereby my new and improved corner structuremay be formed in the outer flanges of both the frontand rear channel sections of the cabinet shell. It will be noted that the apertures. 2(1 and 22' are in line with each other across the blank and so are the apertures 21 and 23.

Further included in the blank 19 are a plurality of recesses cut in edges thereof. Specifically, recesses 24 and 25- are cut in the front edge of the shell adjacent the. apertures 20 and 21 and recesses 26' and 27 are cut in the rear edge of the shell adjacent the apertures 22 and; 23. The, recesses 24 and 26 are generally in line withtheapertures 20. and 22, and the recesses 25 and 27 are generally in line with the apertures 21 and 23. These notches provide for the overlapping efiect mentioned above, which is effected in theouter flanges of the channel sections at the corners of the shell. 7

The apertures 20, 21, 22 and; 23 are all 'generally similar in shape and; they all result in the same. type of corner structure being ultimately formedin the channel sections of the shell member 1. The apertures of course face in difierent directions, andv apertures. 22. and 23 are somewhat smaller than the aperturesltlxand 21. But the same type of corner is still formed by all; and it is be lieved that adescription. of the method in which the aperture 21 is utilized in making the; right-hand corner in. the outer flange 7 of the front channel section will make self-evidentthe similar manner in which the apertures. 20, 22. and 23 are utilized to; provide improved corner structuresin the channel sections at the other cornets of, the shell. The apertures face indifferent directions because they are each provided for the formation. of aditferent corner, the. aperture 21 being provided for'the formation of the left hand front corner, the-apertrue 21 fol-the right-hand front. corner, theaperture 22.

In other words, a single weld both welds? to- Specifically, apertures 20 and 21.

. 4 for the left-hand rear corner, and the aperture 23 for the right-hand rear corner. smaller than the apertures 20 and 21 only because they are designed for use in the smaller rear channel section 6. The recesses 24, 25, 26 and 27 are identical except in size, and their use in the corner construction is the same. Thus only the use of the recess. 25, which is utilized in the same corner as aperture 21, will be described in detail. With reference, to the aperture 21. it will be seen that it is spaced inwardly from the front edge of the shell,.

and that it includes a generally triangular portion 28 and a generally quadrilateral portion 29. The portion 28 is not truly triangular, but, as; shown in. Fig. 4,. it deviates from a triangular shape. only slightly so. that it is best described as being generally triangular. Of the two portions, the generally quadrilateral portion 29 lies more nearly adjacent the front edge of the blank, and the generally triangular portion 28 is positioned in back of it toward the rear edge of the blank. The forward corner 30 of the quadrilateral portion 29 is howeverin line with the rearmost corner 31 of the generally triangular portion 28. Also the longitudinal center line of the recess.

25 is in line with the corners'30 and31.

To formthe cabinet 1 from the blank 19 the front and rear edges thereof are first bent or rolled along the fold lines indicated in Fig. 4-. Any suitable type of apparatus may be used to perform this operation so that the integral channel sections Sand 6 are formed on the edges of the blank. The fold lines at the front edge of blank are indicated respectively at 32', 33, 34, and 35', and the 1 fold lines at therear edge of the blank are indicated respectively at 36, 37, 38 and 39. It will be understood that the blank is not necessarily scored or perforated on these lines but that the. rolling or other folding machinery lies between the fold lines 33 and 34. -Also, the generally triangular portion 28 of the aperture lies mostly between the fold lines 34 and 35. The notch 25 lies between the forward edge of the blank and the fold line 32'.

Due to this positioning of the fold lines, the aperture 21 and the recess 25 result in the notches and recesses shown. in Figs. 5, 6, and 7 being formed in the front channel section 5. As shown in Fig. 5, the recess 25 ends up in the inner single thickness flange 8 once the channelsection 5 is formed. The aperture 21, on the other hand, results in two dissimilar recesses being formed in the twothicknesses of the outer double thickness flange 7. The generally triangular portion 28 forms a generally triangular notch- 28a in the outer thickness 14 of the flange 7 and the generally quadrilateral portion 29 forms a generally quadrilateral recess 29a in the rear thickness 16 of the flange. The edges 40 and 41 of the generally triangular notch 28a in the front thickness 14 are clearly shown in Fig. 6 whereas the edges 42, 43, and 44 of the generally quadrilateral recess 29a in the rear thickness 16 are clearly shown in Fig. 7. It will be noted incidentally that the edge 41 of the notch 28a is not absolutely straight; rather it is slightly deformed so that a tab 45 is formed along the greater portion thereof. As will be. explained hereinafter, this tab 45 is utithickness-flange 8 is generally in line with the corners 30 and 31, and, as indicated by the-line46 in. Fig- 4, the- The apertures 22 and 23 are corners 30 and 31 and the notch 25 lie on the corner line between the sides 2 and 4 of the shell.

Once the channel sections have been rolled or otherwise formed' on the edges of the blank 19, the blank is then ready to be folded into the shell member 1 shown in Fig. 1. This folding is done along the lines 46 and 47 indicated in Fig. 4. As pointed out above, the line 46 extends through the recess 25 and the corners 30 and 31 of the notch 28:: and the recess 29a. This line 46 also extends through the recess 27 and the similar corners of equivalent notch and recess (not shown) formed in the rear channel by the aperture 23. Similarly,.the fold line 47 extends through the recesses 24 and 26 and the similar corners of the notches and recesses (not shown) formed on the front and rear channels by the apertures 20 and 22. Due to this arrangement of the notches and recesses across the fold lines 46 and 47, the folding of the blank along these lines causes a movement of the sides of the notches and recesses as well as bending the principal surface of the blank. As a result and by my invention, the folding not only forms the three walls of the cabinet shell member 1, but also causes my new and improved corner structure to be formed in the channel sections at all four corners of the shell member.

The manner in which the corner structure is formed in the channel sections may best be understood by reference to Figs. 2, 3, 6 and 7 which show the front channel section 5 in the region of the right-hand corner 15 of the shell. As mentioned above, Figs. 2 and 3 show the completed corner structure and Figs. 6 and 7 show the channel section before the bending takes place along the line 46. Before bending, the two edges 40 and 41 form the generally triangular notch 2821' in the front thickness 14 of the outer flange 7. As the bending takes place along the line 46, these edges are moved toward each other until they come together forming the generally mitered joint 13 in the front thickness 14. The joint 13 is not quite a true mitered joint because the tab"45 formed on the edge 41 slightly overlies the edge 40. But the joint may nonetheless be best described as being generally mitered since its edges substantially bisect the angle between the walls 2 and 4. The purpose of the tab 45 overlying the edge 40 after the bending is completed, is to provide metal which may be fused to weld the edges of the joint together.

The bending of the blank along the line 46 also causes a movement of the edges of the generally quadrilateral recess 29a in the rear thickness 16 of the flange 7. Spe cifically the bending causes the edge 42 tomove relative to the edges 43 and 44, or vice versa, so that the edge 42 ends up closely adjacent to the edge 43. Or in other .words, the edges of the recess adjacent the corner 30 are moved almost together. This movement in the rear thickness 16 results in the portion of the rear thickness adjacent the edge 42 to overlap the joint 13 in the front thickness. However, because of the open angle provided in the rear thickness by the edges 43 and 44 no overlapping occurs in the rear thickness itself. The portion of the rear thickness adjacent the edge 42 merely fits into this open angle. The manner in which the portion of the rear thickness adjacent the edge 42 overlaps the joint 13 in the front thickness without any overlapping occurring in the rear thickness itself may be clearly seen by reference to Fig. 3.

The joint 13in the front thickness 14 may be clearly seen in Fig. 2, which shows how the tab 45 on the edge 41 slightly overlies the edge 40 after the corner is formed. Fig. 2 also shows the overlapping and reinforcing eifect of the rear thickness 16 by means of dotted lines included therein. Further, it shows the arrangement which iseffected in the inner flange 8 of the channel. In the inner flange, the notch 25 results in the portion 17 of the inner flange extending. along the wall 4 overlapping the portion 18- extending along the wall 2 of the shell.

It will be understood, of course, that the same basic corner constructionas that described above is formed at all four corners of the shell 1. At all of the corners a generally mitered joint is formed in the front thickness of the outer flange of the respective channel section; and'at all of them a portion of the rear' thickness of the outer flange extending along one of theadjacent walls of the shell overlaps andreinforces the generally mitered joint in the front thickness without any overlapping occurring in the rear thickness itself. Further, at all of these corners a simple overlapping effect is also obtained in the inner flange of the channel section.

After the blank 19 has been bent into the shape of the shell 1', the construction of the shell is then completed by a welding operation at the corner structures formed in the channel sections. This welding is the same at all four corners of the shell. Taking the front righthand corner as typical, the edges 40 and 41 forming the joint 13 are welded together and simultaneously the front and rear thicknesses 14 and 16 of the flange 7 are also welded together. The fusing together'of the two edges 40 and 41and the simultaneous attaching of the overlapping portion of the rear thickness 16 to the front thickness 14 results in'a very strong, rigid corner'in the channel section. The welding is preferably accomplished by applying both heat and pressure at the mitered joint 13. The heat and pressure fuses the tab 45 on the edge 41 and welds together both the edges of the joint and the front and rear thicknesses of the flange. This type of welding, which is commonly known as mash welding, is particularly effective to fuse the tab 45and thereby both weld together the'edges of the joint in the front thickness and the two thicknesses themselves all in a single'operation. The welding, which is the same at all four corners, completes the construction of the shell, and by resulting in particularly strong, rigi'dcorners in the channel sections also results in the formation of a strong, relatively rigid shell member;

From the above it will be seen that I have provided a new and improved cabinet shell member which is strengthened at both its front and rear edges by means of an integral' channel'section. Due to the novel corner structure in these channel sections, astrong, rigid shell is provided. The corner structure itself, although simple to form, is particularly strong because of the manner in which the rear thickness of the outer flange overlaps and reinforces the joint in the front thickness. Besides its strength, a particular advantage of this corner structure is that it is formed bythe same operation as the formationof the shell itself. The bending of the blank so as to form the three walls of the shell also results in my novel corner structure being formed in the channel sections. Then after the shell is bent, only a single welding operation is needed to complete the corner structure. Still another advantage of the structure is, of course, that it allows relatively square, or right-angle corners to be formed in the shell.

With regard to my invention it will be understood that the larger channel can be on either the front or the rear of the cabinet shell, or both channels can be of the same size. Further, in some applications a channel section may be formed on the front or the. rear only, rather than on both. With regard to the welding of the joint 13' it is preferably done by the mash welding described above. However, thewelding could also be done by heat and pressure welding. of the roll seam type. Also it could be done by eliminating the tab 45, spot welding the edges 4i) and 41, and filling in the resulting crevice With a filler. Further, the corner could be joined with brazing material heated and appliedby any of the various well known methods. Therefore by the terms weld and Welding in the following claims it will-be understood that I mean to cover these and all other suitable methods of firmly joining the edges of the corner joint 13 and the'two thicknesses of the front flange 7,;

. In accordance with the patent statutes, I have described what at present is considered to be the preferred embodiment of my invention, but it will be obvious to those skilled inthe art that various changes and modifications may be made therein without departing from the invention, and I, therefore, aim by the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A shell member for a cabinet comprising a single sheet of material bent to form at least two walls of said cabinet, said walls having a stiffening section formed integrally with said sheet and extending along at least a portion of one edge thereof, said section having a double thickness flange and including a corner structure at the corner between said walls, said corner structure including a generally mitered joint in one thickness of said flange and an overlapping and reinforcing of said joint by the other thickness of said flange, the portion of said other thickness extending along one of said walls overlapping said joint without overlapping the portion of said other thickness extending along the other of said walls. 7

2. A shell member for a cabinet comprising a single sheet of material bent to form at least tWo walls of said cabinet, said walls having a stiflening section formed integrally with said sheet and extending along at least a portion of one edge thereof, said section having a double thickness flange and including a corner structure at the corner between said walls, said corn-er structure including a generally mitered joint in one thickness of said flange and an overlapping and reinforcing of said joint by the other thickness of said flange, the portion of said other thickness extending along one-of said walls overlapping said joint without overlapping the portion of said other thickness extending along the other of said walls, and a weld completing said joint in said one thickness and attaching thereto the portion of said other thickness overlapping said joint.

3. A shell member for a cabinet comprising a single sheet of material bent to form three walls of said cabinet, said walls having stiffening channel sections extending along the front and rear edges thereof, said channel sec tions being formed integrally with said sheet and having double thickness outer flanges, the front thicknesses of said outer flanges having generally mitered joints at the corners between said walls, and the rear thicknesses of said outer flanges being arranged at said corners to overlap and reinforce the joints in said front thicknesses without any overlapping in said rear thicknesses themselves, and welds completing said joints in said front thicknesses and attaching thereto the portions of said rear thicknesses overlapping said joints, whereby strong rigid corners are formed in said channel sections and said shell member.

4. A shell member for a cabinet comprising a single sheet of material folded to form at least two walls of said cabinet, said walls having a stiffening channel section extending along at least one wall thereof, said channel section being formed integrally with said sheet and having a double thickness outer flange and an inner flange, the front thickness of said outer flange having a generally mitered joint at the corner between said walls, the rear thickness of said outer flange being arranged at said corner to cause the portion of said rear thickness'extending along one of said walls to overlap and reinforce said joint in said front thickness without overlapping the portion of said rear thickness extending along the other of said walls, whereby a strong rigid corner is formed in said channel section and said shell member.

5. A shell member for a cabinet comprising a single sheet of material folded to form at least two walls of said cabinet, said walls having a stiffening channel section extending along at least one edge thereof, said channel section being formed integrally with said sheet and having a double thickness outer flange and an inner flange, the front thickness of said outer flange having a generally mitered joint at the corner between said walls, the rear thickness of said outer flange being arranged at said corner to cause theportion of said rear thickness extending along one of said walls to overlap and reinforce the joint in said front thickness without overlapping the portion of said rear thickness extending along the other of said Walls, and a Weld completing said joint in said front thickness and attaching thereto the overlapping portion of said rear thickness whereby a strong rigid corner is formed in said channel section and said shell member.

6. The method of simultaneously forming a corner of a cabinet shell member and the side walls thereof from a'sheet metal blank comprising punching out an aperture adjacent one edge of said blank, said aperture having the composite shape of a substantially triangular portion joined to one side of a substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, folding said edge of said blank along the line intersecting said substantially triangular and quadrilateral portions of said aperture to form an integral reinforcing section extending therealong, with said section including a double thickness flange, and with said folding causing said aperture to form a generally triangular notch in one thickness thereof and a quadrilateral recess in the other thickness thereof; and bending said blank on a line perpendicular to the plane of said flange at the apex of said triangular notch thereby to shape said blank into walls of said shell, with said bending moving the edges of said notch together to make a generally mitered corner joint in said one thickness, and also moving the edges of said recess to cause a portion of said other thickness adjacent said recess to overlap and reinforce said joint in said one thickness without overlapping occurring in said other thickness, whereby a shell mc1n her is formed having a strong rigid corner between said walls thereof.

7. The method of simultaneously forming a corner of a cabinet shell member and the side walls thereof from a sheet metal blank comprising punching out an aperture adjacent one edge of said blank, said aperture having the composite shape of a substantially triangular portion joined to one side of substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, folding said edge of said blank along the line intersecting said substantially triangular and quadrilateral portions of said aperture to form an integral reinforcing section extending therealong, with said section including a double thickness flange, and with said folding causing said aperture to form a generally triangular notch in one thickness thereof and a quadrilateral recess in the other thickness thereof; bending said blank on a line perpendicular to the plane of said flange at the apex of said triangular notch thereby to shape said blank into walls of said shell, with said bending moving the edges of said notch together to make a generally mitered corner joint in said one thickness, and also moving the edges of said recess to cause a portion of said other thickness adjacent said recess to overlap and reinforce said joint in said one thickness without overlapping occurring in said other thickness; and welding together both said edges forming said mitered joint and the two thicknesses of said flange in the region of said joint, whereby a shell is formed having a strong rigid corner between the walls thereof.

8. 'The method of simultaneously forming a corner of a cabinet shell member and the side Walls thereof from a sheet metal blank comprising punching out an aperture adjacent one edge of said blank, said aperture having the composite shape of a substantially triangular portion joined to one side of substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, folding said edge of said blank along the line intersecting said substantially triangular and quadrilateral portions of said aperture to form an integral channel section extending therealong, with one flange of said channel section being of a double thickess, and with said folding causing said aperture to form a generally triangular notch in one thickness thereof and a generally quadrilateral recess in the other thickness thereof, the point of said notch and a corner of said recess being disposed over each other; bending said blank on a line with said point of said notch and said corner of said recess to form the walls of said shell, with said bending moving the edges of said notch together to make a generally mitered corner joint in said one thickness, and also moving the edges of said recess adjacent said corner thereof toward each other, thereby to cause a portion of said other thickness adjacent said recess to overlap and reinforce said joint in said one thickness without overlapping occurring in said other thickness; and welding together both said edges forming said mitered joint and the two thicknesses of said flange in the region of said joint, whereby a shell is formed having a strong rigid corner between the walls thereof. 7

9. The method of simultaneously forming a corner of a cabinet shell member and the side walls thereof from a sheet metal blank comprising punching out an aperture adjacent one edge of said blank, said aperture having the composite shape of a substantially triangular portion joined to one side of a substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, folding said edge of said blank along the line intersecting said substantially triangular and quadrilateral portions of said aperture to form an integral channel section extending therealong, with one flange of said channel section being of a double thickness and with said folding causing said aperture to form a generally triangular notch in one thickness thereof and a generally quadrilateral recess in the other thickness, the point of said notch and a corner of said recess being disposed over each other, and one side of said notch having a tab thereon; bending said blank on a line with said point of said notch and said corner of said recess thereby to shape said blank into the walls of said shell, with said bending moving together the edges of said notch to make a generally mitered corner joint in said one thickness but with said tab slightly overlying said joint, said bending also moving the edges of said recess adjacent said corner thereof toward each other thereby to cause a portion of said other thickness adjacent said recess to overlap and reinforce said joint in said one thickness without overlapping occurring in said other thickness; and applying heat and pressure at said mitered joint thereby to fuse said tab and weld together both said edges of said joint and the two thicknesses of said outer flange, whereby a strong rigid corner is formed between said walls of said shell member.

10. The method of simultaneously forming a corner of a cabinet shell member and the side walls thereof from a sheet metal blank comprising punching out a recess in one edge of said blank, and an aperture adjacent said edge and in line with said recess, said aperture having the composite shape of a substantially triangular portion joined to one side of a substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, folding said edge of said blanks along the line intersecting said substantially triangular and quadrilateral portions of said aperture to form an integral channel section extending therealong, with the outer flange of said channel section being of a double thickness and the inner flange being of a single thickness, said recess being positioned in said inner flange, and with said folding causing said aperture to form a generally triangular notch in one thickness of said outer flange and a generally quadrilateral recess in the other thickness of said outer flange, the point of said notch and a corner of said quadrilateral recess being disposed over each other; bending said blank on a line with said point of said notch and said corner of said quadrilateral recess thereby to shape said blank into walls of said shell, with said bending moving the edges of said recess in said inner flange to cause an overlapping effect therein at the corner between said walls, said bending also moving the edges of said notch together to make a generally mitered joint in said one thickness, and moving the edges of said quadrilateral recess to cause a portion of said other thickness adjacent said quadrilateral recess to overlap and reinforce said joint in said one thickness without overlapping occurring in said other thickness; and applying heat and pressure at said mitered joint thereby to weld together both said edges of said joint and the two thicknesses of said outer flange, whereby a shell member having strong rigid corners is formed.

, 11. The method of simultaneously forming a corner of cabinet shell member and the side walls thereof from a sheet metal blank comprising punching out a pair of apertures adjacent each longitudinal edge of said blank, with the apertures adjacent one longitudinal edge being in line with the apertures adjacent the other longitudinal edge, said apertures each having the composite shape of a substantially triangular portion joined to one side of a substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, folding said edges of said blank along the lines intersecting said substantially triangular and quadrilateral portions of said apertures to form an integral channel section extending along each edge, with the outer flange of each channel section being of a double thickness, and with said folding causing each of said apertures to form a generally triangular notch in one thickness of its repective outer flange and a generally quadrilateral recess in the other thickness thereof, the notches and recesses in one channel section being in line with the notches and recesses in the other channel section; bending said blank along the lines joining the points of the notches lying opposite each other thereby to form a three-walled shell from said blank, with said bending moving the edge of said notches together to make a generally mitered joint in said one thicknesses of said outer flanges at each corner of the shell, and also moving the edges of said recesses to cause a portion of said other thicknesses adjacent the recesses to overlap and reinforce the joints in said one thicknesses without overlapping occurring in said other thicknesses themselves, whereby strong rigid corners are formed in said channel sections and said shell member.

12. The method of simultaneously forming the corners of a cabinet shell member and the side walls thereof from a sheet metal blank comprising punching out a pair of apertures adjacent at least one edge of said blank, said apertures having the composite shape of a substantially triangular portion joined to one side of a substantially quadrilateral portion, with said triangular portion being innermost from the associated edge of said blank, with folding said one edge of said blank along the line intersecting said substantially triangular and quadrilateral portions of said apertures to form an integral channel section extending therealong, with the outer flange of the channel section being of a double thickness and the inner flange being of a single thickness, and with said folding causing each of said apertures to form a generally triangular notch in the outer thickness of said outer flange and a generally quadrilateral recess in the inner thickness of said outer flange; bending said blank at the points of said notches thereby to form a three-walled shell member from said blank, said bending moving the edges of said notches together to form a mitered joint in said outer thickness at each corner of said shell, and also moving the edges of said recesses to cause portions of the inner thickness adjacent said recesses to overlap and reinforce said joints in said outer thickness without overlapping occurring in said inner thickness itself; and welding together said edges forming said mitered joint and said outer and inner thicknesses in the region of said joint, whereby strong rigid corners are formed in said shell.

13. A sheet metal blank adapted to be formed into a cabinet shell, said blank comprising a rectangular strip of sheet metal, said blank having a pair of recesses cut in each longitudinal edge thereof, and a pair of apertures spaced from each of said edges and in line with said recesses, each of said apertures including a generally triangular portion and a generally quadrilateral portion, with said triangular portion being innermost from the associated edge of said strip, whereby an integral channel section may be formed on each longitudinal edge of said blank having a single thickness inner flange with a pair of recesses, and a double thicknessouter flange with a pair of generally triangular notches in one thickness and a pair of generally quadrilateral recesses in the other thickness.

14. A sheet metal blank adapted to be formed into a cabinet shell, said blank comprising a rectangular strip of'sheet metal, said blank having a pair of recesses in at least one longitudinal edge thereof and a pair of apertures spaced from said one edge and in line with said recesses,

each of said apertures including a generally triangular portion and a generally quadrilateral portion, with said triangular portion being innermost from said one edge of said rip, whereby an integral channel section may be formed on said one edge having a single thickness inner flange with a pair of recesses, and a double thickness outer flange with a pair of generally triangular notches in one thick ness and a pair of generally quadrilateral recesses in the other thicknessm 15. A sheet metal blank adapted to be formed into a nermost from said edge of said strip, whereby an integral 7 channel section may be formed on said edge of said strip having a single thickness inner flange with a recess, and

a double thickness outer flange with a generally triangular notch inone thickness and a. generally quadrilateral recess in the other thickness, and with said notch and said quadrilateral recess being in line with the inner flange recess.

References Cited in: the file of this patent UNITED STATES PATENTS 1,833,882 Attwood Nov. 24, 1931 2,023,154 Trotter .Q Dec. 3, 1935 2,226,670 Pratt et al Dec. 31, 1940 2,241,266 Mayne et a1. May 6, 1941 2,426,055 Rundell Aug. 19, 1947 

